Aquatic vessel hull

ABSTRACT

A hull ( 10 ) for an aquatic vessel which provides a shark-repelling region about the vessel. The hull ( 10 ) includes two electrodes connected to an electromagnetic field signal generator, which in use, generates an electromagnetic field ( 40 ) about the vessel which repels sharks. The electrodes may be formed from the ends of an electrode cord ( 23 ), or may be formed from conductive ( 24, 25 ) plates ( 20, 21 ) mounted to, or integral with, the hull ( 10 ).

TECHNICAL FIELD

This invention relates to devices and applications of generatingelectromagnetic fields within a body of water to repel aquatic creaturessuch as sharks.

BACKGROUND TO THE INVENTION

Numerous devices are known for the purpose of repelling aquaticcreatures. The majority of these devices are designed to generate anelectromagnetic field in close proximity of a diver or to form a barrieror boundary in the nearby water.

Most studies are conducted on the aquatic creature sub-group ofelasmobranchii, otherwise known as sharks. Most shark repellingapparatus use electromagnetic pulses, delivered into the water bysubmerged antennae or electrodes, to create an appropriateelectromagnetic field in the vicinity of a swimmer, diver or generalwater recreationist.

Various types of pulse signal generators are used, the characteristicsof which include a specification of signal duration, repetition rate,amplitude and pulse rise time. The value or ranges of eachcharacteristic are carefully selected so as to create theelectromagnetic field deemed most effective.

In the past, such signal generators have been disposed on the body ofthe swimmer or as a separate unit to be used in an area that is desiredto be shark-free.

Not only are individuals at risk from being attacked by sharks,sometimes small aquatic vessels such as surfboards, kayaks, rafts andsmall boats can be disturbed by sharks.

It is an object of the present invention to provide a means by whichshark-repelling electromagnetic fields can be generated about an aquaticvessel to reduce the risk of the vessel being disturbed by sharks.

SUMMARY OF THE INVENTION

According to a first aspect of the present invention, there is providedan aquatic vessel hull adapted to support at least two electrodesconnectable to an electromagnetic field signal generator, in use, theelectrodes generating an electromagnetic field in a volume of waterabout the vessel, the electromagnetic field acting to repel selectedaquatic creatures.

Preferably, the aquatic vessel hull includes at least two recesses forreceiving one each of the at least two electrodes, such that the atleast two electrodes do not protrude substantially beyond the uppersurface of the hull.

Preferably, the aquatic vessel hull further includes a channelconnecting said recesses, said channel adapted to accommodate anelectrode cord terminating at each end being one of said at least twoelectrodes.

Preferably, the recesses are formed so as to allow maximum efficiency ofdistribution of the electromagnetic field generated by said electrodeswhen in use.

According to a second aspect of the present invention, there is providedan aquatic vessel hull incorporating at least two electrodes,connectable to an electromagnetic field signal generator, in use, thesaid electrodes generating an electromagnetic field in a volume of waterabout the aquatic vessel, said field acting to repel selected aquaticcreatures.

Preferably, the electrodes do not substantially protrude beyond thesurface of said hull.

Preferably, the electrodes are received in corresponding recesses insaid hull.

Preferably, the electrodes constitute respective ends of a cord, whichis received in a channel in said hull connecting said recesses.

Alternatively, the electrodes consist of respective conductive plates.

Preferably, the recesses are formed so as to allow maximum efficiency ofdistribution of the electromagnetic field generated by said electrodeswhen in use.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a side elevation of an aquatic vessel hull according to apreferred embodiment of the present invention;

FIG. 2 shows a plan view of the top of the aquatic vessel hull of FIG.1;

FIG. 3 shows a plan view of the bottom of an aquatic vessel hull of FIG.1;

FIG. 4 shows the hull of FIG. 3 with the electrode cord inserted;

FIG. 5 shows a detail of the recess for receiving the electric fieldsignal generator;

FIG. 6 shows a cross-sectional view of the recess along the lines A-A′of FIG. 3.

FIG. 7 shows an alternative arrangement of the hull of FIG. 1.

FIG. 8 shows the hull of FIG. 1 in use, generating an electromagneticfield.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

It will be understood that the phrase “aquatic vessel” refers to anysuitable vessel including surfboard, surf rescue board, kayak, sailboat,rowboat, ship and water skis to be worn on the feet of a user.

A typical aquatic vessel hull 10 is shown in side elevation in FIG. 1.Provided in hull 10 is channel 11 for accommodating a cord (not shown)having electrodes at either end of the cord. The type of electrode cordthat will be suitable for this application is the subject of aco-pending PCT Patent Application No PCT/AU02/01297, the contents ofwhich are hereby incorporated by reference. It will be appreciatedhowever, that any other suitable electrode arrangement may be used.

Hollowed recesses 12 and 13 accommodate the electrodes (not shown) ofthe electrode cord which in use, is slid through channel 11 until bothelectrodes are in place in respective recesses 12 and 13 and thensecured in place by any appropriate means.

FIGS. 2 and 3 show these features in a top plan view and a bottom planview respectively.

FIG. 4 show the view of FIG. 3 (bottom view), but with an electrode cord23 inserted in channel 11. Electrodes 24 and 25, being the ends of cord23 are received in recesses 12 and 13 respectively.

Channel 11 may accommodate a fibre glass tube 11 a (see FIG. 6) throughwhich the electrode cord may be slid. Channel 11 is then covered orfilled such that the contour of the exterior surface of hull 10 ismaintained.

Recesses 12 and 13 are shaped such that exposed electrodes are able toradiate effectively from their position within the hull. As can be seenFIG. 6, a preferred range of angles for recesses 12 and 13 is 100°-110°.

Hull 10 also includes a recess or cavity 14 which is sealable with lid15. Recess 14 is adapted to receive and store an electric field signalgenerator. Such signal generators are well known and one such suitablegenerator is described in Australian Patent No 669806. Any suitableelectric field signal generator however, may be used.

Channel 14 a provides a means by which the signal generator can beconnected to the electrodes (see FIG. 5).

It is also within the concept of the present invention to provide a hullhaving incorporated therein electrodes which are connectable to asuitable signal generator. The electrodes may consist of metal plates ora conductor of any other suitable configuration, which may be attachedto, or form an integral portion of the hull. For example, a portion ofthe front end of the hull may be made from or include a metal or otherconductive plate providing a first electrode, while a portion of theback end of the hull may be made from a metal or other conductive plate,forming a second electrode. Such an arrangement is shown in FIG. 7, inwhich electrode plates 20, 21 are shown incorporated within hull 10.Upon connection to a suitable signal generator, these plates may radiatethe required electromagnetic field to produce a shark-deterring regionwithin the water about the hull.

FIG. 8 shows the hull of FIG. 1 incorporating the cord with electrodeshoused in channels 12 and 13 (not shown), in use in a body of water 30.

When activated the signal generator (not shown) causes the electrodes(not shown) to generate electromagnetic field 40 about hull 10, forminga shark-repelling region about the vessel. This reduces the risk of ashark attacking the vessel, or a person who is in the water, and nearthe vessel, such as a person who has fallen off or out of the vessel.

While the above has been described with reference to a preferredembodiment, it will be understood that further modifications andalterations may be made within the scope of the present invention.

1. An aquatic vessel hull adapted to support at least two electrodesconnectable to an electromagnetic field signal generator, in use, theelectrodes generating an electromagnetic field in a volume of waterabout the vessel, the electromagnetic field acting to repel selectedaquatic creatures.
 2. An aquatic vessel hull according to claim 1,wherein said aquatic vessel hull includes at least two recesses forreceiving one each of the at least two electrodes, such that the atleast two electrodes do not protrude substantially beyond the surface ofthe hull.
 3. An aquatic vessel hull according to claim 2 wherein saidaquatic vessel hull further includes a channel connecting said recesses,said channel adapted to accommodate an electrode cord terminating ateach end in one of said at least two electrodes.
 4. An aquatic vesselhull according to claim 3 wherein said recesses are formed so as toallow maximum efficiency of distribution of the electromagnetic fieldgenerated by said electrodes when in use.
 5. An aquatic vessel hullincorporating at least two electrodes, connectable to an electromagneticfield signal generator, in use, the said electrodes generating anelectromagnetic field in a volume of water about the aquatic vessel,said field acting to repel selected aquatic creatures.
 6. An aquaticvessel hull according to claim 5 wherein said at least two electrodes donot substantially protrude beyond the surface of said hull.
 7. Anaquatic vessel hull according to any one of claims 5 or 6 wherein saidat least two electrodes are received in corresponding recesses in saidhull.
 8. An aquatic vessel hull according to claim 7 wherein said atleast two electrodes constitute respective ends of a cord, which isreceived in a channel in said hull connecting said recesses.
 9. Anaquatic vessel hull according to claim 6 wherein said at least twoelectrodes consist of respective conductive plates.
 10. An aquaticvessel hull according to claim 7 wherein said recesses are formed so asto allow maximum efficiency of distribution of the electromagnetic fieldgenerated by said electrodes when in use.